This project will use neuroanatomical, behavioral, and pharmacological methods to characterize neurological changes underylying behavioral changes in development. The behavioral preparation involves the transition from thermal-dependent to olfactory-dependent locomotion in the golden hamster pup during the second week of postnatal life. The proposed experiments will continue work which has implicated the olfactory tubercle as a site of maturational events responsible for the behavioral change. Knife cuts of tubercle projections, cannulation of dopaminergic and cholinergic blockers and agonists into the tubercle, and neuroanatomical analysis of normal maturational changes and reorganization following deafferentation will be performed. The hypothesis to be tested is that the normal loss of thermal-dependent locomotion is the result of maturational changes in a tubercle-based cholinergic system. It is hoped that these studies will contribute to formulation of general principles of neurological maturation underlying behavioral development.